Mobilization of Haematopoietic Stem Cells CD34+ in Patients undergoing Elective Lung Resection: Observational Pilot Study

Background: Blood haematopoietic stem cells expressing the CD34 cell surface marker (CD34+) may differentiate under appropriate stimula into a variety of cell types to repair damaged organs. Purposes of this study were to verify whether lung surgical trauma can activate bone marrow mobilizing peripheral CD34+ cells and the time course of their activation.Methods and findings: In fifty-one patients undergoing elective surgical lung resection under general anesthesia, ASA II-III, without chronic obstructive pulmonary disease, blood samples for white blood cells (WBC) and circulating blood CD34+ were collected before surgery (T0), at 24 (T24h) and 72 (T72h) hours, 5 (T5d) and 7 (T7d) days postoperatively. CD34+ cells quantification was performed by flow cytometry. A hierarchical clustering analysis identified two clusters based on the CD34+ time course: in cluster #1 (14 patients), CD34+ decreased by 46% on T24h (p=0.0023 vs T0) and then increased constantly reaching 230% on T7d (p=0.00016 vs all previous time points), in cluster #2 (37 patients), CD34+ remained stable throughout the study. Patients entering cluster #1 were younger (58+4 years vs 66+1 years, p=0.03), had a higher baseline CD34+ count (on T0 CD34+ 2.55+1.5 n/10-3 vs 1.2+0.57 n/10-3, p=0.0023) and the pre-operative FEV1/FVC was significantly higher (95.66 vs 76.6, p=0.02).Conclusions: Our data show that peripheral blood CD34+ are mobilized from the bone marrow in patients undergoing lung resection and their count seems to be correlated with WBC and CD34+ basal values and with patients age.